(i) Technical Field
The present invention relates to a compressor and a vacuum machine.
(ii) Related Art
There is known a compressor and a vacuum machine which compress and discharge intake air by a piston which reciprocates within a cylinder by a motor. Japanese Patent Application Publication No. 2004-183498 discloses such a compressor.
The temperature of the motor, which is used for such a compressor or a vacuum machine, increases, when the motor drives. When the temperature of the motor increases, the heat is transferred to the cylinder, so the temperature thereof increases. Thus, for example, the piston might wear to adversely influence parts and the life of the compressor itself or the vacuum machine itself.
Also, air is adiabatically compressed within the cylinder, so that the temperature of the adiabatically compressed air becomes high. Thus, the compressor or the vacuum machine might be continuously used while heating up. In this case, for example, the piston wears to adversely influence parts and the life of the compressor itself or the vacuum machine itself. Also, there is a case where the compressed air blew a catalyst to react, depending on a device supplied with the compressed air. In such a case, when the compressed air temperature is high, the reaction of the catalyst might not proceed.
Japanese Patent Application Publication No. 2004-183498 discloses a fan for cooling the compressor is arranged in an axial direction of a motor. However, there is a problem with the large height in the axial direction. Further, in Japanese Patent Application Publication No. 2004-183498, an inner rotor type motor is used. Thus, there is another problem that the inner rotor type motor has a torque smaller than that of an outer rotor type motor having the same size as the inner rotor type motor.